共查询到19条相似文献,搜索用时 190 毫秒
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五味子提取物高效液相色谱分析方法的优化 总被引:3,自引:1,他引:2
针对五味子乙醇提取物的复杂体系,借助于复杂样品分析系统软件(CSASS),根据组分在4次简单线性梯度下42个峰的保留时间,快速准确地计算出各组分的液相色谱保留参数a,c值和峰形参数σ,W1/2。借助这些参数,对五味子色谱的分离情况进行高精度仿真预测。在此基础上,应用移动重叠分辨分离图和谱图仿真技术,发展了计算机辅助的五味子提取物的高效液相色谱全局优化方法。在优化条件下,五味子提取物的高效液相色谱分析可在40 min内完成,且常量成分和部分低含量成分都能够得到较好的分离。所建立的方法已成功地用于五味子中化合物保留时间及峰形的预测,并在此基础上对其色谱分离条件进行优化。 相似文献
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反相高效液相色谱法分离制备蜂毒肽类似物 总被引:1,自引:0,他引:1
应用高效制备液相色谱法,对5种合成的蜂毒肽类似物分离制备。当用极性较强的洗脱液做流动相时,主峰的保留时间短,且主峰和前后的杂质峰不能很好的分开;随着洗脱液极性减弱至某一值时,主峰和杂质峰的保留时间均向后延长,且时间间隔加大,可以成功地对多肽样品进行分离制备。有多肽分子中各氨基酸保留常数加和值的方法可以预测不同多肽的保留时间,为选择分离纯化多肽所需的流动相提供了参考作用。经半制备分离纯化后的产物用分析型RP-HPLC测定达到了很高的纯度,氨基酸分析结果表明得到了所需的肽段,可以用于下一步的研究工作。 相似文献
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在采用反相液相色谱或亲和色谱完成蛋白质等大分子分离时,根据溶质保留值随溶剂梯度变化曲线上突变点的差别,可以通过累加进样分离法进行样品制备或直接柱内富集分析,但这一方法并非在任意条件下、对任何样品都适用。该文根据不同形式的保留值方程从理论上探讨了样品保留值与进样时间差、梯度洗脱速率等实验条件之间的关系;结果表明:两次进样的出峰时间差与进样时间间隔成正比关系,也与其在等度情况下的容量因子有关。样品中的两种组分在间隔进样时的流出时间差主要由两组分的容量因子决定,当样品中存在两种以上保留性能相近组分时,若保证指定的分离度,进样时间间隔存在一极大值,超出该范围,分离条件将不能满足 相似文献
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根据毛细管电色谱中溶质保留值与有机改性剂种类和浓度之间的相互关系,首次实现了毛细管电色谱有机流动相双二元双台阶分离。利用此方法分离含12种芳香族化合物的混合样品,各组分在六次连续进样中保留时间的RSD(%)值均在1.65%以内,并将样品的分离时间缩短到等度洗脱方式下的三分之一。这说明该方法分离复杂样品快速、可靠。此外还推导了双二元双台阶分离方式下溶质保留值的预测公式,并对该公式的准确性进行了检验,预测值与实测值间的相对误差在5.73%以内。 相似文献
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Kostanyan AE 《Journal of chromatography. A》2011,1218(37):6412-6418
Basing on the perfect replacement approach the equilibrium cell model is developed to describe the separation process in elution-extrusion counter-current chromatography (EECCC). As is known, EECCC consists of three steps: classical elution, sweeping elution, and extrusion. The perfect replacement approach means that during sweeping elution step, the mobile phase contained in the column moves and interacts with the "old" stationary phase in the same mode as during the classical elution step; the "new" and "old" stationary phases do not mix; and after the contacting with the mobile phase the concentration of solutes in the "old" stationary phase remains constant and this stationary phase volume is pushed ahead to the exit of the column. Equations are presented allowing the simulation of the chromatogram of solutes eluted from the column with the mobile phase during the elution period and the chromatogram of solutes pushed out of the column with the stationary phase during the extrusion period of EECCC. These equations can help to choose the optimal conditions for conducting elution-extrusion counter-current chromatography. 相似文献
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The basic principle of optimal method called “moving overlapping resolution mapping method” to select the optimal binary mobile phase composition of multi-step linear gradient liquid chromatography is discussed with simultaneously considering effects of position of solute inside the column and mobile phase composition on peak resolution and retention value, then a BASIC program based on this principle is developed in IBM-PC computer. The validities of both principle of optimization and BASIC program are confirmed by separation of samples containing bile acids and PAHs in RP-HPLC. 相似文献
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利用HCI程序确定儿茶酚化合物的反相高效液相色谱最佳分离条件 总被引:1,自引:0,他引:1
有效地确定了反相高效液相色谱分离儿茶酚化合物的最佳条件。在水和甲醇的二元流动相里分别加入乙酸缓冲液,利用基于ln k=ln kw +SF, k=A+B/F, ln k=L+MF+NF2 (F是流动相中有机物甲醇的体积分数)等保留因子的一次或二次方程式的塔板理论得到色谱分离结果;利用保留原理得到等度和梯度洗脱的最佳条件。得出最佳初始流动相是含0.1%乙酸的水和含0.1%乙酸的甲醇(体积比为75∶25)的混合溶液;梯度洗脱条件:初始流动相保持15 min,然后用10 min的时间将上述二元流动相的体积比线性变换成50∶50,直到完成全部分离。通过实验证实该计算结果与实验值相近。 相似文献
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A neutral octadecyl monolithic (ODM) column for RP capillary electrochromatography (RP-CEC) has been developed. The ODM column was prepared by the in situ polymerization of octadecyl acrylate (ODA) as the monomer and trimethylolpropanetrimethacrylate (TRIM) as the crosslinker, in a ternary porogenic solvent containing cyclohexanol, ethylene glycol, and water. The ODM column exhibited cathodal EOF over a wide range of pH and ACN concentration in the mobile phase despite the fact that it was devoid of any fixed charges. It is believed that the EOF is due to the adsorption of ions from the mobile phase onto the surface of the monolith thus imparting to the neutral ODM column the zeta potential necessary to support the EOF required for mass transport across the monolithic column. Furthermore, the adsorption of mobile phase ions to the neutral monolith modulated solute retention and affected the separation selectivity. The wide applications of the neutral ODM column were demonstrated by its ability to separate a wide range of small and large solutes, both neutral and charged. While the separation of the neutral solutes was based on RP retention mechanism, the charged solutes were separated on the basis of their electrophoretic mobility and hydrophobic interaction with the C18 ligands of the stationary phase. As a typical result, the neutral monolithic column was able to separate peptides quite rapidly with a separation efficiency of nearly 200,000 plates/m, and this efficiency was exploited in tryptic peptide mapping of standard proteins, e. g., lysozyme and cytochrome C, by isocratic elution. 相似文献
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In reversed-phase liquid chromatography, the retention mechanism of solute has been studied under linearly programmed gradient mobile-phase conditions. The separation of a mixture of four purine compounds (purine, theobromine, theophylline, and caffeine) was considered as a practical case in two binary mobile phase systems, water/methanol and water/acetonitrile. The retention model which describes how the retention factor is related to the mobile-phase composition has been developed in various mathematical forms to predict the retention time in both linear and gradient elutions. For a pulse injection of sample, two important factors, the retention time and the bandwidth of solute, might be computable to predict the elution profiles estimated by the distribution function, such as the Gaussian distribution function. In this work, a prediction method based on the analogue of the retention model was proposed to calculate the bandwidth in linear gradient elutions. Band broadening was caused by the different migration velocities of the front and rear ends of the solute band in a chromatographic column. Therefore, the migration behaviors of the front and rear ends of the solute band were explained with the same retention model which had been used to predict the retention time of solute. For the well retained solutes, theophylline and caffeine, the predicted bandwidth and experimentally obtained bandwidth showed good agreement in both isocratic and gradient elutions. 相似文献
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The main feature of counter-current chromatography (CCC) is that the stationary phase is a liquid as well as the mobile phase. The retention volumes of solutes are directly proportional to their distribution coefficients K(D) in the biphasic liquid system used in the CCC column. Solutes with high K(D) coefficients are highly retained in the column. The back-extrusion method (BECCC) uses the fact that the liquid stationary phase, that contains the retained solutes, can be easily moved. Switching the column inlet and outlet ports without changing the liquid phase used as the mobile phase causes the rapid collapse of the two immiscible liquid phases inside the column, the previously stationary phase being gathered at the new column outlet. Then this previously stationary liquid phase is extruded outside the CCC column carrying the retained solutes. The back-extrusion method is tested with a standard mixture of five compounds and compared with the recently described elution-extrusion method. It is shown that the chromatographic resolution obtained during the back-extrusion step is good because the solute band broadening is minimized as long as the solute is located inside the "stationary" phase. However, a major drawback of the BECCC method is that all solutes are split between the liquid phases according to their distribution ratios when the CCC column equilibrium is broken. The change of flowing direction should be done after a sufficient amount of mobile phase has flushed the column in the classical mode, eluting solutes with small and medium distribution ratios. Otherwise, a significant portion of the solutes will stay in the mobile phase inside the column and produce a broad peak showing after the stationary phase extrusion. 相似文献